<!DOCTYPE html>
<style>
div.zero::before { content: '0: '; }
div.one::before { content: '1: '; }
</style>
<div>
    <div class='zero'>Zero</div>
    <div class='zero'>Zero</div>
    <div class='zero'>Zero</div>
    <div class='one'>One</div>
</div>
</html>
